What do you understand by multi-valued attribute? How is it different from complex and composite attribute? Illustrate by giving suitable example.

Attributes may be defined as characteristics that reflect the features of the entity. In case of a person these characteristics may be height, weight, name, date of birth, etc. and in case of accounts it may be code, type, name, etc. These attributes own a value which is stored in database as data.

Multi-valued attribute is an attribute that has multiple values. For example, flavour of ice-creams. It is a multi-valued attribute as the flavour of an ice-cream can be strawberry, vanilla, butter-scotch, etc. In other words, multi-valued attributes are the different characteristics of a same entity.

Composite attributes are the combination or aggregate of related attributes. These attributes can be further divided into small portions to represent the independent meaning of some basic attributes. For example, contact details which is generally divided into telephone numbers (with STD code), mobile number and e-mail Ids.

Complex attributes are formed by grouping together the attributes of composite and multi-valued attributes. To show the grouping of components of composite attributes, the parenthesis ( ) are used and to show the grouping of components of complex attributes, the brackets { } are used.